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| author | Tim Northover <tnorthover@apple.com> | 2014-05-02 17:25:02 +0000 |
|---|---|---|
| committer | Tim Northover <tnorthover@apple.com> | 2014-05-02 17:25:02 +0000 |
| commit | 820e041a3c45430f75fb8c22083b58d5c6bc8153 (patch) | |
| tree | 51e573eb1b01efd878dcf99af7c254f1c493a8e7 | |
| parent | ea3aca8b67cef0079ccf4a4c0935b1bab0727fc7 (diff) | |
| download | bcm5719-llvm-820e041a3c45430f75fb8c22083b58d5c6bc8153.tar.gz bcm5719-llvm-820e041a3c45430f75fb8c22083b58d5c6bc8153.zip | |
DAGCombine: prevent formation of illegal ConstantFP nodes.
llvm-svn: 207850
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 15 | ||||
| -rw-r--r-- | llvm/test/CodeGen/ARM64/fp-contract-zero.ll | 14 |
2 files changed, 24 insertions, 5 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 290f2a1ea27..de715e4791e 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -7181,11 +7181,16 @@ SDValue DAGCombiner::visitFNEG(SDNode *N) { // (fneg (fmul c, x)) -> (fmul -c, x) if (N0.getOpcode() == ISD::FMUL) { ConstantFPSDNode *CFP1 = dyn_cast<ConstantFPSDNode>(N0.getOperand(1)); - if (CFP1) - return DAG.getNode(ISD::FMUL, SDLoc(N), VT, - N0.getOperand(0), - DAG.getNode(ISD::FNEG, SDLoc(N), VT, - N0.getOperand(1))); + if (CFP1) { + APFloat CVal = CFP1->getValueAPF(); + CVal.changeSign(); + if (Level >= AfterLegalizeDAG && + (TLI.isFPImmLegal(CVal, N->getValueType(0)) || + TLI.isOperationLegal(ISD::ConstantFP, N->getValueType(0)))) + return DAG.getNode( + ISD::FMUL, SDLoc(N), VT, N0.getOperand(0), + DAG.getNode(ISD::FNEG, SDLoc(N), VT, N0.getOperand(1))); + } } return SDValue(); diff --git a/llvm/test/CodeGen/ARM64/fp-contract-zero.ll b/llvm/test/CodeGen/ARM64/fp-contract-zero.ll new file mode 100644 index 00000000000..f982cbb7f5e --- /dev/null +++ b/llvm/test/CodeGen/ARM64/fp-contract-zero.ll @@ -0,0 +1,14 @@ +; RUN: llc -mtriple=arm64 -fp-contract=fast -o - %s | FileCheck %s + + +; Make sure we don't try to fold an fneg into +0.0, creating an illegal constant +; -0.0. It's also good, though not essential, that we don't resort to a litpool. +define double @test_fms_fold(double %a, double %b) { +; CHECK-LABEL: test_fms_fold: +; CHECK: fmov {{d[0-9]+}}, xzr +; CHECK: ret + %mul = fmul double %a, 0.000000e+00 + %mul1 = fmul double %b, 0.000000e+00 + %sub = fsub double %mul, %mul1 + ret double %sub +}
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